How to Make It
Preheat the oven to 375°. Peel the pears and cut them in half lengthwise. Using a melon baller or a teaspoon, scoop out the cores. Rub the pears with the cut lemon to prevent browning.
Melt the butter in an ovenproof skillet just large enough to hold the pears in a single layer. Add the brown sugar and maple syrup and cook over moderately low heat, stirring, until the sugar is dissolved. Add the pears and turn them several times to coat with the syrup. Arrange the pears, cut side down, in a single layer and bake for about 30 minutes, basting occasionally with pan juices, until just softened and golden.
Transfer the pears to a platter and keep warm. If necessary, add a little water to the skillet to thin the syrup. Remove from the heat and stir in the vanilla. Pour the syrup over the pears and serve warm or at room temperature.